Android: Wie zu stoppen, media player onclick einer Schaltfläche

Ich habe einen play und stop button. Wenn ich führen Sie die folgenden codes, Play-Taste geht auch. Aber wenn ich auf die stop-Taste, ich bin immer ein force close Meldung.

Ich bin neu in der android dev. Vielen Dank im Voraus! 🙂

package com.example.hellomedia;

import java.io.IOException;


import android.app.Activity;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.os.Handler;
import android.view.View;
import android.widget.TextView;

public class HelloMedia extends Activity {


    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        final MediaPlayer mPlayer = MediaPlayer.create(HelloMedia.this, R.raw.nicholas);

        setContentView(R.layout.main);

        final Handler mHandler = new Handler();

        final TextView customTextBG = (TextView) findViewById(R.id.customTextBG);
        final TextView customTextHL = (TextView) findViewById(R.id.customTextHL);

        customTextBG.setText("Nicholas was… \n\nOlder than sin, ");
        customTextHL.setText("");

        final String words[] = {
                "Nicholas ", //0
                "was... \n\n", //1
                "Older ", //2
                "than ", //3
                "sin, ", //4
        };

        final long startEndTime[][]={
                {   //start time
                    1148,//0,0
                    1826, //0,1
                    2766,//0,2
                    3079,//0,3
                    3549,//0,4

                },
                {   //end time
                    1357,//1,0
                    2192, //1,1
                    3027,//1,2
                    3183,//1,3
                    3966,//1,4
                }
            };



        customTextBG.setText("Nicholas was… \n\nOlder than sin, ");
        customTextHL.setText("");




        View.OnClickListener handler = new View.OnClickListener(){
            public void onClick(View v) {

                switch (v.getId()) {
                    case R.id.widget30: //PLAY

                        if( !mPlayer.isPlaying() ){

                            try {
                                mPlayer.prepare();
                            } catch (IllegalStateException e) {
                                //TODO Auto-generated catch block
                                e.printStackTrace();
                            } catch (IOException e) {
                                //TODO Auto-generated catch block
                                    e.printStackTrace();
                            }

                            mPlayer.start();

                            mHandler.post(new Runnable(){

                                    public void run(){ 
                                    final long currentPos = mPlayer.getCurrentPosition();

                                        int x = 0;
                                        while( x < 102){
                                            if( currentPos > startEndTime[0][x] && currentPos < startEndTime[1][x] ){//0
                                            customTextHL.append(words[x]);
                                            words[x]="";
                                        }
                                        x++;
                                    } mHandler.postDelayed(this, 1);
                                    }

                              });
                        }

                        break;

                    case R.id.widget31: //RESET

                        mHandler.post(new Runnable(){

                            public void run(){ 
                                customTextBG.setText("Nicholas was… \n\nOlder than sin, ");
                                customTextHL.setText("");
                            }

                      });

                        mPlayer.stop();
                        mPlayer.release();

                        break;
                }
            }
        };

        //BUTTONS
        findViewById(R.id.widget30).setOnClickListener(handler); //PLAY
        findViewById(R.id.widget31).setOnClickListener(handler); //RESET

    }
}

Meine main.xml code:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
android:id="@+id/widget29"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
xmlns:android="http://schemas.android.com/apk/res/android"
>
<TextView
android:textStyle="bold" 
android:id="@+id/customTextBG" 
android:textSize="18sp" 
android:text="@+id/customTextBG" 
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/widget31"
android:layout_alignParentLeft="true"
>
</TextView>
<TextView
android:textStyle="bold" 
android:id="@+id/customTextHL" 
android:textSize="18sp" 
android:text="@+id/customTextHL" 
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/widget31"
android:layout_alignParentLeft="true"
android:textColor="#00FF00"
>
</TextView>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_toRightOf="@+id/widget30"
android:text="@string/reset" android:id="@+id/widget31">
</Button>
<Button
android:id="@+id/widget30"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:text="@string/play">
</Button>
</RelativeLayout>